Probing the non-thermal physics of stellar bow shocks using radio observations
- Autores
- Martinez, Javier Rodrigo; del Palacio, S.; Bosch Ramon, V.
- Año de publicación
- 2023
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- Context. Massive runaway stars produce bow shocks in the interstellar medium. Recent observations revealed radio emission from a few of these objects, but the origin of this radiation remains poorly understood. Aims: We aim to interpret this radio emission and assess under which conditions it could be either thermal (free-free) or non-thermal (synchrotron), and how to use the observational data to infer physical properties of the bow shocks. Methods: We used an extended non-thermal emission model for stellar bow shocks for which we incorporated a consistent calculation of the thermal emission from the forward shock. We fitted this model to the available radio data (spectral and intensity maps), including largely unexplored data at low frequencies. In addition, we used a simplified one-zone model to estimate the gamma-ray emission from particles escaping the bow shocks. Results: We can only explain the radio data from the best sampled systems (BD+43°3654 and BD+60°2522) assuming a hard electron energy distribution below ∼1 GeV, a high efficiency of conversion of (shocked) wind kinetic power into relativistic electrons (∼1 − 5%), and a relatively high magnetic-to-thermal pressure ratio of ηB ∼ 0.2. In the other systems, the interpretation of the observed flux density is more ambiguous, although a non-thermal scenario is also favoured. We also show how complementary observations at other frequencies can allow us to place stronger constraints in the model. We also estimated the gamma-ray fluxes from the HII regions around the bow shocks of BD+43°3654 and BD+60°2522, and obtained luminosities at GeV energies of ∼1033 erg s−1 and 1032 erg s−1, respectively, under reasonable assumptions. Conclusions: Stellar bow shocks can potentially be very efficient particle accelerators. This work provides multi-wavelength predictions of their emission and demonstrates the key role of low-frequency radio observations in unveiling particle acceleration processes. The prospects of detections with next-generation observatories such as SKA and ngVLA are very promising. Finally, BD+43°3654 may be detected in GeV in the near future, while bow shocks in general may turn out to be non-negligible sources of (at least leptonic) low-energy cosmic rays.
Fil: Martinez, Javier Rodrigo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina
Fil: del Palacio, S.. Chalmers University of Technology; Suecia
Fil: Bosch Ramon, V.. Universidad de Barcelona; España - Materia
-
radiation mechanisms: non-thermal
radiation mechanisms: thermal
Astrophysics - High Energy Astrophysical Phenomena
radio continuum: general - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/271135
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oai:ri.conicet.gov.ar:11336/271135 |
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CONICET Digital (CONICET) |
spelling |
Probing the non-thermal physics of stellar bow shocks using radio observationsMartinez, Javier Rodrigodel Palacio, S.Bosch Ramon, V.radiation mechanisms: non-thermalradiation mechanisms: thermalAstrophysics - High Energy Astrophysical Phenomenaradio continuum: generalhttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1Context. Massive runaway stars produce bow shocks in the interstellar medium. Recent observations revealed radio emission from a few of these objects, but the origin of this radiation remains poorly understood. Aims: We aim to interpret this radio emission and assess under which conditions it could be either thermal (free-free) or non-thermal (synchrotron), and how to use the observational data to infer physical properties of the bow shocks. Methods: We used an extended non-thermal emission model for stellar bow shocks for which we incorporated a consistent calculation of the thermal emission from the forward shock. We fitted this model to the available radio data (spectral and intensity maps), including largely unexplored data at low frequencies. In addition, we used a simplified one-zone model to estimate the gamma-ray emission from particles escaping the bow shocks. Results: We can only explain the radio data from the best sampled systems (BD+43°3654 and BD+60°2522) assuming a hard electron energy distribution below ∼1 GeV, a high efficiency of conversion of (shocked) wind kinetic power into relativistic electrons (∼1 − 5%), and a relatively high magnetic-to-thermal pressure ratio of ηB ∼ 0.2. In the other systems, the interpretation of the observed flux density is more ambiguous, although a non-thermal scenario is also favoured. We also show how complementary observations at other frequencies can allow us to place stronger constraints in the model. We also estimated the gamma-ray fluxes from the HII regions around the bow shocks of BD+43°3654 and BD+60°2522, and obtained luminosities at GeV energies of ∼1033 erg s−1 and 1032 erg s−1, respectively, under reasonable assumptions. Conclusions: Stellar bow shocks can potentially be very efficient particle accelerators. This work provides multi-wavelength predictions of their emission and demonstrates the key role of low-frequency radio observations in unveiling particle acceleration processes. The prospects of detections with next-generation observatories such as SKA and ngVLA are very promising. Finally, BD+43°3654 may be detected in GeV in the near future, while bow shocks in general may turn out to be non-negligible sources of (at least leptonic) low-energy cosmic rays.Fil: Martinez, Javier Rodrigo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: del Palacio, S.. Chalmers University of Technology; SueciaFil: Bosch Ramon, V.. Universidad de Barcelona; EspañaEDP Sciences2023-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/271135Martinez, Javier Rodrigo; del Palacio, S.; Bosch Ramon, V.; Probing the non-thermal physics of stellar bow shocks using radio observations; EDP Sciences; Astronomy and Astrophysics; 680; 12-2023; 1-140004-6361CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/10.1051/0004-6361/202347720info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/202347720info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:29:00Zoai:ri.conicet.gov.ar:11336/271135instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 10:29:00.886CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
Probing the non-thermal physics of stellar bow shocks using radio observations |
title |
Probing the non-thermal physics of stellar bow shocks using radio observations |
spellingShingle |
Probing the non-thermal physics of stellar bow shocks using radio observations Martinez, Javier Rodrigo radiation mechanisms: non-thermal radiation mechanisms: thermal Astrophysics - High Energy Astrophysical Phenomena radio continuum: general |
title_short |
Probing the non-thermal physics of stellar bow shocks using radio observations |
title_full |
Probing the non-thermal physics of stellar bow shocks using radio observations |
title_fullStr |
Probing the non-thermal physics of stellar bow shocks using radio observations |
title_full_unstemmed |
Probing the non-thermal physics of stellar bow shocks using radio observations |
title_sort |
Probing the non-thermal physics of stellar bow shocks using radio observations |
dc.creator.none.fl_str_mv |
Martinez, Javier Rodrigo del Palacio, S. Bosch Ramon, V. |
author |
Martinez, Javier Rodrigo |
author_facet |
Martinez, Javier Rodrigo del Palacio, S. Bosch Ramon, V. |
author_role |
author |
author2 |
del Palacio, S. Bosch Ramon, V. |
author2_role |
author author |
dc.subject.none.fl_str_mv |
radiation mechanisms: non-thermal radiation mechanisms: thermal Astrophysics - High Energy Astrophysical Phenomena radio continuum: general |
topic |
radiation mechanisms: non-thermal radiation mechanisms: thermal Astrophysics - High Energy Astrophysical Phenomena radio continuum: general |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
Context. Massive runaway stars produce bow shocks in the interstellar medium. Recent observations revealed radio emission from a few of these objects, but the origin of this radiation remains poorly understood. Aims: We aim to interpret this radio emission and assess under which conditions it could be either thermal (free-free) or non-thermal (synchrotron), and how to use the observational data to infer physical properties of the bow shocks. Methods: We used an extended non-thermal emission model for stellar bow shocks for which we incorporated a consistent calculation of the thermal emission from the forward shock. We fitted this model to the available radio data (spectral and intensity maps), including largely unexplored data at low frequencies. In addition, we used a simplified one-zone model to estimate the gamma-ray emission from particles escaping the bow shocks. Results: We can only explain the radio data from the best sampled systems (BD+43°3654 and BD+60°2522) assuming a hard electron energy distribution below ∼1 GeV, a high efficiency of conversion of (shocked) wind kinetic power into relativistic electrons (∼1 − 5%), and a relatively high magnetic-to-thermal pressure ratio of ηB ∼ 0.2. In the other systems, the interpretation of the observed flux density is more ambiguous, although a non-thermal scenario is also favoured. We also show how complementary observations at other frequencies can allow us to place stronger constraints in the model. We also estimated the gamma-ray fluxes from the HII regions around the bow shocks of BD+43°3654 and BD+60°2522, and obtained luminosities at GeV energies of ∼1033 erg s−1 and 1032 erg s−1, respectively, under reasonable assumptions. Conclusions: Stellar bow shocks can potentially be very efficient particle accelerators. This work provides multi-wavelength predictions of their emission and demonstrates the key role of low-frequency radio observations in unveiling particle acceleration processes. The prospects of detections with next-generation observatories such as SKA and ngVLA are very promising. Finally, BD+43°3654 may be detected in GeV in the near future, while bow shocks in general may turn out to be non-negligible sources of (at least leptonic) low-energy cosmic rays. Fil: Martinez, Javier Rodrigo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina Fil: del Palacio, S.. Chalmers University of Technology; Suecia Fil: Bosch Ramon, V.. Universidad de Barcelona; España |
description |
Context. Massive runaway stars produce bow shocks in the interstellar medium. Recent observations revealed radio emission from a few of these objects, but the origin of this radiation remains poorly understood. Aims: We aim to interpret this radio emission and assess under which conditions it could be either thermal (free-free) or non-thermal (synchrotron), and how to use the observational data to infer physical properties of the bow shocks. Methods: We used an extended non-thermal emission model for stellar bow shocks for which we incorporated a consistent calculation of the thermal emission from the forward shock. We fitted this model to the available radio data (spectral and intensity maps), including largely unexplored data at low frequencies. In addition, we used a simplified one-zone model to estimate the gamma-ray emission from particles escaping the bow shocks. Results: We can only explain the radio data from the best sampled systems (BD+43°3654 and BD+60°2522) assuming a hard electron energy distribution below ∼1 GeV, a high efficiency of conversion of (shocked) wind kinetic power into relativistic electrons (∼1 − 5%), and a relatively high magnetic-to-thermal pressure ratio of ηB ∼ 0.2. In the other systems, the interpretation of the observed flux density is more ambiguous, although a non-thermal scenario is also favoured. We also show how complementary observations at other frequencies can allow us to place stronger constraints in the model. We also estimated the gamma-ray fluxes from the HII regions around the bow shocks of BD+43°3654 and BD+60°2522, and obtained luminosities at GeV energies of ∼1033 erg s−1 and 1032 erg s−1, respectively, under reasonable assumptions. Conclusions: Stellar bow shocks can potentially be very efficient particle accelerators. This work provides multi-wavelength predictions of their emission and demonstrates the key role of low-frequency radio observations in unveiling particle acceleration processes. The prospects of detections with next-generation observatories such as SKA and ngVLA are very promising. Finally, BD+43°3654 may be detected in GeV in the near future, while bow shocks in general may turn out to be non-negligible sources of (at least leptonic) low-energy cosmic rays. |
publishDate |
2023 |
dc.date.none.fl_str_mv |
2023-12 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://hdl.handle.net/11336/271135 Martinez, Javier Rodrigo; del Palacio, S.; Bosch Ramon, V.; Probing the non-thermal physics of stellar bow shocks using radio observations; EDP Sciences; Astronomy and Astrophysics; 680; 12-2023; 1-14 0004-6361 CONICET Digital CONICET |
url |
http://hdl.handle.net/11336/271135 |
identifier_str_mv |
Martinez, Javier Rodrigo; del Palacio, S.; Bosch Ramon, V.; Probing the non-thermal physics of stellar bow shocks using radio observations; EDP Sciences; Astronomy and Astrophysics; 680; 12-2023; 1-14 0004-6361 CONICET Digital CONICET |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/10.1051/0004-6361/202347720 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/202347720 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
dc.format.none.fl_str_mv |
application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
EDP Sciences |
publisher.none.fl_str_mv |
EDP Sciences |
dc.source.none.fl_str_mv |
reponame:CONICET Digital (CONICET) instname:Consejo Nacional de Investigaciones Científicas y Técnicas |
reponame_str |
CONICET Digital (CONICET) |
collection |
CONICET Digital (CONICET) |
instname_str |
Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.name.fl_str_mv |
CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.mail.fl_str_mv |
dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar |
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1844614295073062912 |
score |
13.070432 |